This package provides some useful and efficient functions for treating polynomial matrices (i.e. matrices whose entries are univariate polynomials with rational or symbolic coefficients). The supplied functions compute the classical Smith, Hermite and McMillan forms. Each function has two versions: one returning only the form and one returning the form and the unimodular transformations leading to it. Several other functions are defined: computation of left and right GCD's, lcm's, quotients, remainders, row/column proper forms, full rank and coprimality tests, extended polynomial GCD, solution of diophantine equations. All functions work on matrices of polynomials in z or z^-1.